Electrolytic time delay capsule with plastic cup electrode holder

ABSTRACT

An electrolytic timer capsule is constructed of an outer cylindrical closed end case and an inner insulated upside down cup enclosing an electrolyte solution to contact the closed end of the case. The case comprises one electrode and the other is a U-shaped wire extending through the cup with an intermediate section immersed in the electrolyte solution to be etched away until broken. The manufacturing process for the capsule comprises a series of simplified operations comprising insert of the cup into the case, filling with electrolyte and sealing with epoxy resin.

States Patent 1191 Jones, Jr.

[ Oct. 30, 1973 '[22] Filed:

[ ELECTROLYTIC TIME DELAY CAPSULE WITH PLASTIC CUP ELECTRODE HQLDER [75]Inventor: John Paul Jones, Jr., Wayne, Pa.

[73] Assignee: Compuline Corporation, King of Prussia, Pa.

July 17, 1972 21 Appl. No.: 272,431

[52] 11.8. C1. 317/230, 29/570 [51] Int. Cl Hing 9/00 [58] Field ofSearch 317/230; 29/570 [56] References Cited UNITED STATES PATENTS8/1958 Hilton 2,932,153 4/1960 Bernard et al. 317/230 3,356,911 12/1967Galvagni 317/230 3,365,626 l/1968 Mohler et a1. 317/230 Voeten 317/230Peck 317/230 Primary Examiner-John W. Huckert Assistant Examiner-AndrewJ. James Attorney-Laurence R. Brown [5 7 ABSTRACT An electrolytic timercapsule'is constructed of an outer cylindrical closed end case and aninner insulated upside down cup enclosing an electrolyte solution tocontact the closed end of the case. The case comprises one electrode andthe other is a U-shaped wire extending through the cup with anintermediate section immersed in the electrolyte solution to be etchedaway until broken. The manufacturing process for the capsule comprises aseries of simplified operations comprising insert of the cup into thecase, filling with electrolyte and sealing with epoxy resin.

10 Claims, 1 Drawing Figure ELECTROLYTIC TIME DELAY CAPSULE WITH PLASTICCUP ELECTRODE HOLDER This invention relates to electrolytic timerdevices operable to electroplate from a metallic electrode and moreparticularly it relates to expendible electrolytic timer devices whichsignify the expiration of a predetermined time period by rupture of theconductive path of an electric conductor and their methods ofmanufacture. Circuits for such timer devices are described in my U.S.Pat. No. 3,355,731. Prior art timer device construction is typified bymy copending application U.S. Ser. No. 106,481 filed Ian. 14, 1971.

If a timer device is expendible it must be simple and low in cost, andyet must be accurate and precise in signifying a predetermined timeperiod. The use of electrolyte solutions under seal requiremanufacturing techniques to assure long shelf life and operation withoutleaking, changing physical and performance dimensions or creatingoperating hazards. In particular construction techniques must be simpleand subject to automated assembly to assure uniformity of performance atlow cost.

Also the cost of assembly of an expendible timer device is significantand therefore simple and effective configuration of a device(hereinafter referred to as a capsule) is desirable.

It is therefore an object of this invention to provide an improved timercapsule which satisfiesthe foregoing conditions.

A particular object of the invention is to provide a simple-capsuleconfiguration which is inexpensive to manufacture without disturbing thetiming accuracy and methods of construction thereof.

The foregoing objectives are realized in accordance with this inventiontogether with further features and advantages by provision of a metallicelectrode which is plated away in the form of a single piece of wirehaving an intermediate portion passed through a plastic cup whichreceives electrolyte solution. The plastic cup is force fit into anelectrode can and has a funnel for receiving electrolyte and serving toseal the electrolyte inside before surrounding with an epoxy.

I A preferred embodiment of the invention is shown in the single FIGUREof the drawing showing a capsule in elevation section view partially toshow the constructional features thereof.

In the capsule assembly, an outer copper can 1 serves as one electrodeholding an electrolyte solution 2 in which a second electrode in theform of a U-shaped continuous copper wire is inserted. The wireelectrode 3 has two end conductor leads 4,5 by which detection is madeof the rupture of the U-shaped portion within the electrolyte by platingaway on the bottom surface 6 of the can electrode 1 by electrolyticaction when a current is passed between the electrodes.

Inside the can electrode 1 is the inverted cup assembly 7 made ofpolypropylene plastic to hold the electrolyte solution 2. A compressionring 8 is formed by an integral outwardly extending lip about the outerbottom edge conforming in shape to the interior bottom of the can 1thereby to form a liquid tight seal with the end of the electrode can Iexposing only the plating surface 6 at the inner closed end of the camelectrode 1 to the electrolyte 2. The integral seal ring is compressedabout 0.020 feet when inserted with the can to form a hermetic seal.

The cup assembly 7 includes a keyway mating structure for orienting thecup position during automated assembly in inserting the electrode wireassembly 4, 5. Thus a precision indented keyway portion 9 is located bymeans of a rough location finder in the form of indented keyway portion10 for orientation on automated assembly jigs or the like.

The walls 11 of the cup assembly 7 are tapered to permit the influx of aliquid epoxy sealing solution 12 thereabout without bubbling or voids.The epoxy seal is by this construction isolated from the electrolyte bythe seal ring 8 and thus is not subject to deterioration over long shelfstorage periods or high operation temperatures from the action of theelectrolyte solution 2, which could cause leaks along the sides of thecan. Also the seal ring 8 prevents epoxy 12 from fouling the electrodesurface 6 during the manufacturing process.

Another feature of the cup assembly 7 is the heat scalable aperture tube13 to funnel the electrolyte into the cavity 2 between the two cups 1and 7. This permits injection of electrolyte 2 by a hypodermic needle orthe like at the upper mouth entry 14 until it reaches a level 15 at thethroat of the funnel tube 13. After the electrolyte 2 is inserted, themouth 14 of the funnel tube 13 is heat sealed as shown in phantom lines16 to enclose the electrolyte 2 and entrap an air bubble 17 whichpermits expansion of the electrolyte without danger of bursting orleakage.

Lead funnels 18 are provided for receiving and passing the ends 4, 5 ofthe single wire copper electrode unit 3 through the cup bottom 19. Adetent tab 20 is coined into the lead to permit the electrode unit 3 tosnap into place in the cup and be held therein firmly against the ribbonlike U-shaped portion of the electrode unit 3 (described in theaforementioned copending application).

MANUFACTURING METHOD In the first assembly step, the electrode unit 3 iscoined or forged from a continuous copper wire, bent into its U-shapeand inserted into the inverted cup 7. All units are keyed fororientation and automatic handling with appropriate machinery.

The cup assembly 7 is then pressed into the copper cup electrode 1 toform the hermetic seal at theinterface with compression ring 8.

A first measured epoxy seal charge 12 is then entered into the shell tojust cover the leads near the tabs 20 where they pass through the cupassembly bottom 19, so that just enough epoxy can run down around theleads to form a complete seal in the area of lead funnels 18. The epoxyis then cured before further processing.

To insert the electrolyte a dispensing needle is inserted through mouth14 of the funnel neck 13 and a measured charge is inserted to reachlevel 15, and as the needle is withdrawn, a heated head presses upon themouth 14 melting and sealing it closed at 16.

1 Immediately thereafter a further epoxy charge is inserted in region 30to reach just below the lip 30 of the can electrode l to produce acompletely hermetically sealed assembly.

After curing of the epoxy the can electrode 1 is then cleaned by adetergent and the leads and can are electroplated with tin on allexposed portions, after which a final charge 32 of epoxy is inserted togive a finished appearance and to provide a minicus 33 about the leads4, S. This provides a finished appearance and further assures a completeseal about the leads.

Because a solid copper can 1 and a solid copper wire 3 are used with nodissimilar metals within the active electrolyte area 2 there is nopossible deterioration at high temperatures or over long storage periodsthat could cause a battery effect. Also the mechanical arrangement ofthe assembly prevents any possible inter nal shorting of the inner leadsto the outer case.

What is claimed is:

1. In an electrolytic timer capsule having two electrodes and anelectrolyte therebetween, the combination comprising, an outer cupforming a first of said electrodes, an inner cup of plastic materialinserted upside down into said electrode to form a cavity confining theelectrolyte between said cups, a second electrode comprising a length ofwire, and means passing the second of said electrodes through said innercup with a continuous portion extending into said electrolyte cavity,and two ends extending out of the capsule so that the wire may beelectrolytically broken by electric current passed between theelectrodes and detected by a .therethrough two wires, and said secondelectrode comprising abent wire with two free ends extending throughsaid two funnels and held in said base by detent tabs formed in saidwire at either end of said aperture funnels in said base.

6. A capsule as defined in claim 1 having mating structure for orientingsaid inner cup in a known position within said outer cup, and having adetent member on said outer cup in a fixed position.

7. A capsule as defined in claim 1 wherein said second electrode andsaid outer cup electrode are both of the same metal.

8. A capsule as defined in claim 1 with the inner cup having a rim of adimension greater than the inner di ameter of the outer cup and insertedupside down in said outer cup by force fit inside said outer cup to forma hermetically sealed cavity between the cups for receiving saidelectrolyte.

9. A capsule as defined in claim Shaving a scalable aperture tubeextending from the bottom of said inner cup for introducing electrolyteinto said cavity after said inner cup is force fit into said outer cup.

10. A capsule as defined in claim 1 wherein said continuous portion isU-shaped with the ends disposed away from the bottom of the electrodecup.

Disclaimer 3,769,557.J0hn Paul Jones, J?., Wayne, Pa. ELECTROLYTIC TIMEDELAY CAPSULE WITH PLASTIC CUP ELECTRODE HOLDER. Patent dated Oct. 30,1978. Disclaimer filed Mar. 22, 1974, by the assignee, Oompulz'neOowpomtz'on. Hereby enters this disclaimer to claims 1 and 10 of saidpatent.

[Oflioz'al Gazette J2me 10, 1.975.]

Disclaimer 3,7 69,557.J07m Paul J ones, Jvn, Wayne, Pa. ELECTROLYTICTIME DELAY CAPSULE WITH PLASTIC CUP ELECTRODE HOLDER. Patent dated Oct.30, 1973. Disclaimer filed Mar. 22, 1974, by the assignce, Oompulz'neOwpomtz'on.

Hereby enters this disclaimer to claims 1 and 10 of said patent.

[Ozfi'oial Gazette J2me 10, 1.975.]

1. In an electrolytic timer capsule having two electrodes and anelectrolyte therebetween, the combination comprising, an outer cupforming a first of said electrodes, an inner cup of plastic materialinserted upside down into said electrode to form a cavity confining theelectrolyte between said cups, a second electrode comprising a length ofwire, and means passing the second of said electrodes through said innercup with a continuous portion extending into said electrolyte cavity,and two ends extending out of the capsule so that the wire may beelectrolytically broken by electric current passed between theelectrodes and detected by a change of continuity between said two ends.2. A capsule as defined in claim 1 with said cavity having electrolytetherein extending only partially into said aperture tube to provide anair pocket within said tube, the tube being closed and sealed above saidair pocket.
 3. A capsule as defined in claim 2 with an epoxy sealdeposited between said inner and outer cups to substantially cover theouter portions of said inner cup exposed inside said outer cup.
 4. Acapsule as defined in claim 1 wherein said plastic cup comprises amember having tapered walls terminating in an integral outwardlyprojecting view ring of dimensions slightly less than the inner diameterof said outer cup.
 5. A capsule as defined in claim 1 having twoaperture funnels in the base of said plastic cup for receivingtherethrough two wires, and said second electrode comprising a bent wirewith two free ends extending through said two funnels and held in saidbase by detent tabs formed in said wire at either end of said aperturefunnels in said base.
 6. A capsule as defined in claim 1 having matingstructure for orienting said inner cup in a known position within saidouter cup, and having a detent member on said outer cup in a fixedposition.
 7. A capsule as defined in claim 1 wherein said secondelectrode and said outer cup electrode are both of the same metal.
 8. Acapsule as defined in claim 1 with the inner cup having a rim of adimension greater than the inner diameter of the outer cup and insertedupside down in said outer cup by force fit inside said outer cup to forma hermetically sealed cavity between the cups for receiving saidelectrolyte.
 9. A capsule as defined in claim 8 having a sealableaperture tube extending from the bottom of said inner cup forintroducing electrolyte into said cavity after said inner cup is forcefit into said outer cup.
 10. A capsule as defined in claim 1 whereinsaid continuous portion is U-shaped with the ends disposed away from thebottom of the electrode cup.